Remove last references to opt_nogpu.

cgminer.c

@@ -95,7 +95,6 @@ int opt_dynamic_interval = 7;
 int opt_g_threads = -1;
 int gpu_threads;
 bool opt_restart = true;
-bool opt_nogpu;
 
 struct list_head scan_devices;
 static bool devices_enabled[MAX_DEVICES];

driver-opencl.c

@@ -1012,8 +1012,6 @@ static void opencl_detect(bool hotplug)
 {
 	int i;
 
-	if (opt_nogpu)
-		return;
 	nDevs = clDevicesNum();
 	if (nDevs < 0) {
 		applog(LOG_ERR, "clDevicesNum returned error, no GPUs usable");

miner.h

@@ -969,7 +969,6 @@ extern bool opt_api_listen;
 extern bool opt_api_network;
 extern bool opt_delaynet;
 extern bool opt_restart;
-extern bool opt_nogpu;
 extern bool opt_worktime;
 extern int swork_id;